Field of the invention
[0001] The present invention relates to a slider unit for a tertiary air duct between a
clinker cooler and a calciner of a clinker kiln plant.
Description of the related art
[0002] Cement clinker, also short referred to as clinker, is usually produced in a rotary
kiln. The clinker is discharged from the hot end of the rotary kiln ontb a cooling
grate of a clinker cooler. The clinker resting on top of the cooling grate is cooled
by a gas or a mixture of gases, usually air. The air is strongly heated, at least
in the area close to the kiln. This strongly heated air has a temperature of approximately
750-1300°C and carries a high amount of dust. The heated air is extracted from the
clinker cooler at the kiln hood and/or the cooler roof and fed via a so-called tertiary
air duct to some other processing stage. The air is referred to as tertiary air accordingly.
This tertiary air is normally used for pre-processing of the raw meal and mostly fed
to a calciner or an upstream combustion or gasification unit, such as a combustion
chamber. The term calciner is used in this application as a synonym for a "raw meal
pre-processing unit" being fed with tertiary air as heat and/or oxygen source.
[0003] The raw materials which are necessary for the production of cement clinker are at
least partly decarbonised in the calciner, using the thermal energy provided by the
tertiary air directly, whereas the oxygen contained in the tertiary air is used for
the combustion of fuel in the secondary firing. The permanent optimisation of energy
efficiency in cement producing plants results in an increase of tertiary air temperature.
At the same time, the tertiary air volume per time unit decreases. The increasing
use of secondary fuels like coal with high ash content, petrol coke etc. particularly
increases the amount of dust per m
3 of tertiary air, i.e. the dust load in the tertiary air. In order to prevent clinker
dust from clogging the tertiary air duct in the long term, the flow speed inside the
tertiary air duct is increased. The higher temperature and the high dust load, in
combination with the higher flow speed, cause higher wear on the refractory lining
inside the tertiary air duct.
[0004] When the clinker kiln line is started up, the tertiary air duct has to be initially
closed. So called shutoff devices are used for this purpose. In the most simple case
these are plate-like sliders, which are inserted into the tertiary air duct orthogonally
to the flow direction, thus closing it during start-up of the clinker kiln line. Foldable
flaps are as well used as shutoff devices. After start-up ("Ramp up") the shutoff
devices should be completely open. The present invention is based on the observation
that the shutoff devices are, beyond their design, often used to control the amount
of tertiary air per time unit as described in
DE 10 2006 023 980 A1, for example when the clinker kiln line is not operated at full production. In this
case the shutoff devices are only inserted partly into the tertiary air duct, for
example to split up the supply air for the combustion in the kiln and the calciner,
thus ensuring oxidizing conditions at the kiln inlet.
[0005] When the shutoff devices do not close the tertiary air duct completely, they are
subject to strong wear as the clinker dust contained in the tertiary air is highly
abrasive. As a result, the shutoff element is abraded and thereby shortened to the
extent, that it cannot reliably seal the tertiary air duct. A normal restart of the
clinker kiln line after an unscheduled shutdown is not possible without exchanging
the shutoff device.
[0006] Another problem is that the shutoff element deforms due to thermal stress which can
result in jamming of the shutoff device and an adjustment of the same becomes impossible.
[0007] US 4,275,763 discloses a double slide valve for finely divided solid catalysts in fluid catalytic
cracking units. The temperatures of the fluid may reach up to 1.400°F, i.e. about
760°C. However, the temperature of the tertiary air stream from the clinker cooler
to the calciner is typically about 1200°C. The valve would thus never withstand the
conditions in a tertiary air duct of a cement clinker kiln line. Besides that the
US-Patent discloses a double slide valve with two valve plates being in different
horizontal planes and aligned 180° to each other. Both valve plates are used for controlling
a desired flow of material. If the first plate is worn off the second one is used
instead.
[0008] US 4,612,955 discloses a valve for gaseous flow streams in fluid catalytic cracking units. The
technical teaching is -briefly summarized -to use a valve plate with an edge wear
tab having an increased mounting area to thereby facilitate mounting and anchoring
the edge wear tab to the valve plate.
[0009] US 2,494,634 teaches a damper for exposure to high temperatures. The damper has only a single
slide. The technical teaching of D3 can be briefly summarized to provide a water cooled
damper, in which all metal parts being exposed to hot gases are water cooled.
Summary of the invention
[0010] The present invention is based on the task, to facilitate both a reliable shutting
off of a tertiary air duct and a control of the tertiary air flow.
[0011] This task is solved by a slider unit according to claim 1. Further improvements of
the invention are specified in the dependent claims.
[0012] In particular, the slider unit can be inserted into a tertiary air duct of a clinker
kiln line, hence it is located in the tertiary air flow between a clinker cooler and
a calciner of the clinker kiln line. Accordingly the slider unit can have a duct section,
which can be inserted into the tertiary air duct. A preferably plate-like shutoff
device can be inserted into the tertiary air duct in order to shut off the tertiary
air duct, in other words close it completely. In addition to the shutoff device the
slider unit contains at least one control device which can be inserted into the tertiary
air duct in order to reduce its cross section. The functions shutoff and control are
separated in the slider unit. Therefore the shutoff device is not subject to noteworthy
wear, as it is only inserted into the tertiary air duct to close it completely. Hence
its functioning is ensured permanently. The control device, however, can be inserted
continuously into the tertiary air duct in order to reduce its cross section continuously
and is in this position exposed to the tertiary air flow and should be designed accordingly.
Preferably, the control device is equipped with a heat resistant cladding of refractory
bricks or similar material at least on its side facing towards the tertiary air flow.
Refractory here is not only stone-like, heat resistant material with 10 to 45 per
cent alumina content like fire clay but, according to the general linguistic usage,
all heat resistant, in particular stone-like cladding, in particular cladding made
of ceramics or ceramic elements.
[0013] For simplification there is no differentiation in the following text between air,
a gas or a mixture of gases used as cooling agent for the clinker. The terms air or
tertiary air are consequently not limited to the typical gas composition of air.
[0014] Preferably the control device is supported by the shutoff device on its downwind
side that is the side facing away from the tertiary air flow. Therefore the slider
unit is particularly small. Preferably, the control device is located upwind, that
is the side facing towards the tertiary air flow, of its guide. Hence the guide is
covered and therefore shielded against the tertiary air flow by the control device.
[0015] Preferably, the length of the control device is significantly less than the diameter
of the duct section, as it does not have to shut off the tertiary air duct. To cover
the usual control range a length of 1/3 to 2/3 of the duct diameter is sufficient.
Consequently it requires only a small amount of space next to the tertiary air duct
when withdrawn completely from the tertiary air duct. In addition it takes less refractory
material to protect the smaller slider, which reduces costs.
[0016] Preferably the shutoff device has at least two parallel movable shutoff segments.
The length of each of the two shutoff segments is particularly preferable less or
equal to the length of the control device. By this method the space required for the
slider unit next to the tertiary air duct can be kept particularly small. For example,
the shutoff device can have at least two plates, movable in parallel to each other
which can be inserted into the duct section.
[0017] Particularly preferable, at least a first shutoff segment is movable in a guidance
of at least another shutoff segment. Therefore the guidance of the first shutoff segment
is not exposed to the tertiary air flow when the shutoff device is open and thus protected
from damage through the tertiary air.
[0018] Particularly preferable, at least the first shutoff segment of a multi-segment shutoff
device has at least one catch for another shutoff segment of the shutoff device. Thus
it is sufficient to actuate the first shutoff segment to open or close the tertiary
air duct.
[0019] Particularly preferable, the shutoff device and the control device are mounted suspended
above the tertiary air duct and can be lowered into the tertiary air duct. Therefore
no thrust needs to be applied to close the shutoff device or to insert the control
device. Flexible connecting elements, like chains or belts can be used instead of
push rods, which further reduces the required space for the slider unit.
[0020] Preferably, the control device consists of at least one carrier, which is connected
to means for adjusting the control device, for example to at least one chain hoist.
The carrier is preferably clad with refractory material e.g. bricks, particularly
preferably together with an isolating layer, for example insulating wool, located,
between the carrier and the refractory bricks. Preferably, the bricks can be bolted
to the carrier, securing the isolating layer. Such a control device has a good price/lifetime
ratio.
[0021] Preferably the control device and/or the shutoff device has at least one channel
for a cooling agent. This further improves durability.
[0022] The duct section of the tertiary air duct in which the control device and/or the
shutoff device are to be inserted has preferably at least one slot through which the
control device and/or the shutoff device can be inserted. The duct section has preferably
lateral guides, in the direction of movement, in which the shutoff device and/or the
control device are movable.
Description of Drawings
[0023] In the following, the invention will be described by way of example, without limitation
of the general inventive concept, by referring to examples of embodiment and with
reference to the drawings.
Figure 1 shows a slider unit for a tertiary air duct,
Figure 2 shows a partly assembled slider unit,
Figure 3 shows a detail of a slider unit,
Figure 4 shows a detail of a slider unit, and
Figure 5 shows a detail of an alternative shutoff device.
[0024] The slider unit 1 in figure 1 has a duct section 10, which can be installed in a
tertiary air duct and is clad with refractory material 12. Hence, the slider unit
can be installed in a tertiary air duct as a module, which makes assembly easier.
A box-like support structure 20 large enough to accommodate a control device 60 (shown
inserted into the tertiary air duct) and a shutoff device 80 (shown partly inserted)
is located on top of the duct section 10. The support structure 20 houses the control
device 60 and the shutoff device 80 in their retracted positions. On the upper side
of the support structure 20 are drives 26, 28 for retracting the control device 60
or the shutoff device 80, respectively, out of the duct section 10 into the box like
support structure 20. Thereby, the tertiary air duct can be opened completely. The
shutoff device 80 and the control device 60 can be retracted or inserted into the
duct section 10 independently (see fig. 2). In the refractory material are grooves
14, 16 as guides for the control device 60 and the shutoff device 80 (see fig. 1).
Additionally, the shutoff device 80 is guided by the guides 18 on both sides. Simply
speaking the guides 18 are rails that extend from the support structure 20 through
a slot in the refractory cladding into the duct section.
[0025] The shutoff device 80 consists of two shutoff segments are moveable parallel to each
other, the example shown here is plate-shaped, further referred to as plates 82, 83.
Plate 82 is located in front of plate 83 in a guide of the rear plate 83 (see fig.
3). The front plate 82 has a lower edge 86 or lower narrow side 86 which is adapted
to the contour of the lower part of the duct section 10. Fastenings 84 holding the
front plate 82 are attached on its upper narrow side 88. This upper narrow side 88
is at least approximately horizontal. The lateral narrow sides 92 are at least approximately
parallel to each other and have a vertical longitudinal axis. The rear plate 83 is
supported by the upper narrow side of the front plate 82. For this purpose the rear
plate 83 is equipped with steel profiles 85 on its front side used as catches 85,
the free ends of which are angled downward at least approximately parallel to the
front plate 82. These catches 85 bear on the upper narrow side 88 of the front plate
82.
[0026] For closing the duct section 10, the front plate 82 together with the rear plate
83 are lowered from the support structure 20 into the tertiary air duct until the
rear plate 83 is located in the groove 16 and at least the lower part of the lateral
narrow sides 93 bears on the groove. Consequently, the shapes of the lower part of
the narrow sides 93 are adapted to the contour of the duct section 10. When the rear
plate 83 bears on the inner wall of the duct section 10, the front plate 82 slides
further downwards, being guided by the steel profiles 85 attached to the rear plate
83. In its final position, the front plate also bears on the groove 16. The duct section
10 is now sealed for tertiary air. To open the tertiary air duct the front plate 82
can be lifted upwards via the fastenings 84. During lifting, the front plate 82 is
guided by the groove 16 in the wall of the duct section 10 as well as by the lateral
steel profiles 85. Approximately halfway up, the front plate 82 attaches to the rear
plate 83 or the upper steel profiles 85, respectively from below and also lifts the
rear plate, until both plates have reached their final position inside the support
structure 20. The duct section 10 is now open (not shown). As both plates 82, 83 are
guided parallel to each other in a telescope-like manner, the minimum construction
height of the carrier is significantly reduced. Therefore such a shutoff device 80
can be retrofitted even in problematic locations.
[0027] The control device 60 has a carrier plate 62 having fastening elements 64 attached
to its upper end. The carrier plate 62 is suspended from the fastening elements 64
(see fig. 4). Heat resistant isolating material 66, for example mineral wool felt,
is attached to the front and rear sides of the carrier plate 62 as well as to the
narrow sides (at least the two lateral and the lower narrow side). The isolating material
66 is clad with refractory bricks 70. The refractory bricks are bolted to the carrier
plate 62 by bolts 68. The refractory bricks 70 have through holes 72, which have a
larger diameter on the side facing away from the carrier plate 62. The larger sections
of the through holes 72 are used to receive nuts 69, thus protecting the nuts and
the projecting parts of the bolts 68 from abrasion by clinker dust. Preferably, the
holes are sealed by a curing heat resistant matter.
[0028] Unlike the shutoff device 80 shown in figures 1 to 3, the shutoff device 80 depicted
in figure 5 consists of only one plate 82, which hangs from fastening elements 84
and can be lifted out color lowered into a duct section 10 by a drive 28. The shutoff
device 80 has only one plate, which cannot cover the complete cross section of the
tertiary air duct, but the plate is lowered behind the control device, so that it
is sufficient to seal the remaining open part of the tertiary air duct below the control
device with the single plate.
List of reference numerals
[0029]
- 1
- slider unit
- 10
- duct section / tertiary air duct
- 12
- heat resistant material/cladding (i.e. refractory or ceramics)
- 14
- groove
- 16
- groove
- 18
- guide
- 20
- carrier / support structure / housing
- 26
- drive
- 28
- drive
- 60
- control device
- 62
- carrier plate
- 64
- fastening element
- 66
- isolating material
- 68
- bolt
- 69
- nut
- 70
- refractory bricks / heat resistant cladding
- 72
- through hole
- 80
- shutoff device
- 82
- plate / shutoff segment
- 83
- plate / shutoff segment
- 84
- fastening element
- 85
- catch / steel profile
- 86
- lower edge / lower narrow side of the front plate
- 87
- lower edge / lower narrow side of the rear plate
- 88
- upper narrow side of the front plate
- 89
- upper narrow side of the rear plate
- 92
- lateral narrow sides of the front plate
- 93
- lateral narrow sides of the rear plate
1. A slider unit (1) for a tertiary air duct between a clinker cooler and a calciner
of a clinker kiln line having at least one shutoff device (80) which can be inserted
into the tertiary air duct (10) to shut it off and does not further reduce the cross
section of the tertiary air duct (10),
characterised in that
the slider unit (1) further comprises at least one control device (60) being configured
for being inserted into said duct for reducing the cross section of a section of the
tertiary air duct.
2. The slider unit (1) of claim 1,
characterised in that
the control device (60) is arranged on the upwind facing side of the shutoff device
(80).
3. The slider unit (1) of claim 2,
characterised in that
the control device (60) is supported by the shutoff device (80) on its downwind facing
side.
4. The slider unit (1) of one of the preceding claims,
characterised in that
the shutoff device (80) has at least two shutoff segments (82, 83) guided in parallel
to each other.
5. The slider unit (1) of claim 4,
characterised in that
at least a first of the shutoff segments (82) is movable in a guide of at least another
of the shutoff segments (83).
6. The slider unit (1) of claim 4 or 5,
characterised in that
at least one of the shutoff segments (82) has at least one catch (85) for at least
one other shutoff segment (83) of the shutoff device (80).
7. The slider unit (1) of one of the preceding claims,
characterised in that
the control device (60) has at least one carrier (62) with heat resistant cladding.
8. The slider unit (1) of one of the preceding claims,
characterised in that
the control device (60) has a self-supporting plate of heat resistant material.
9. The slider unit (1) of one of the preceding claims,
characterised in that
the control device (60) and/or the shutoff device (80) has at least one channel for
a cooling agent.
10. The slider unit (1) of one of the preceding claims,
characterised in that
the surface of the side of the control device facing towards the tertiary air flow
is smaller than the cross section of the tertiary air duct.
11. An installation for producing cement clinker with at least
- a kiln,
- a calciner,
- a clinker cooler and
- a tertiary air duct for conveying pre-heated air to the calciner
characterised in that
the installation has at least one slider unit (1) of one of the preceding claims.
1. Eine Schiebereinheit (1) für eine Tertiärluftleitung zwischen einem Klinkerkühler
und einem Kalzinator einer Klinkerfertigung, aufweisend zumindest eine Absperrvorrichtung
(80), welche in die Tertiärluftleitung (10) eingesetzt werden kann, um sie abzusperren
und welche ansonsten den Querschnitt der tertiären Luftleitung (10) nicht weiter verringert,
dadurch gekennzeichnet dass
die Schiebereinheit (1) weiterhin zumindest eine Steuerungseinheit (60) umfasst, welche
konfiguriert ist, um in diese Leitung eingesetzt zu werden, um den Querschnitt eines
Abschnitts der Tertiärluftleitung zu verringern.
2. Schiebereinheit (1) nach Anspruch 1,
dadurch gekennzeichnet dass
die Steuerungseinheit (60) an der Strömung zugewandten Seite der Absperrvorrichtung
(80) angeordnet ist.
3. Schiebereinheit (1) nach Anspruch 2,
dadurch gekennzeichnet dass
die Steuerungseinheit (60) an seiner der Strömung abgewandten Seite der Absperrvorrichtung
(80) gestützt ist.
4. Schiebereinheit (1) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet dass
die Absperrvorrichtung (80) zumindest zwei parallel zueinander geführte Absperrsegmente
(82, 83) aufweist.
5. Schiebereinheit (1) nach Anspruch 4,
dadurch gekennzeichnet dass
zumindest ein erstes der Absperrsegmente (82) in einer Führung des zumindest einen
anderen der Absperrsegmente (83) beweglich ist.
6. Schiebereinheit (1) nach Anspruch 4 oder 5,
dadurch gekennzeichnet dass
zumindest eines der Absperrsegmente (82) zumindest eine Abfangung (85) für zumindest
ein anderes Absperrsegment (83) der Absperrvorrichtung (80) aufweist.
7. Schiebereinheit (1) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet dass
die Steuerungseinheit (60) zumindest einen Träger (62) mit einer hitzebeständigen
Verkleidung aufweist.
8. Schiebereinheit (1) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet dass
die Steuerungseinheit (60) eine selbsthaltende Platte aus einem hitzebeständigen Material
aufweist.
9. Schiebereinheit (1) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet dass
die Steuerungseinheit (60) und/oder die Absperrvorrichtung (80) zumindest einen Kanal
für ein Kühlmittel aufweisen.
10. Schiebereinheit (1) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet dass
die Oberfläche der Seite der Steuerungseinheit, die dem Tertiärluftstrom zugewandt
ist, kleiner ist als der Querschnitt der tertiären Luftleitung.
11. Eine Anordnung zur Herstellung von Zementklinker mit zumindest,
- einem Brennofen,
- einem Kalzinierer,
- einem Klinkerkühler, und
- einer tertiären Luftleitung, um vorgewärmte Luft zu dem Kalzinierer zu befördern,
dadurch gekennzeichnet dass
die Anordnung zumindest eine Schiebereinheit (1) nach einem der vorhergehenden Ansprüche
aufweist.
1. Une unité coulissante (1) pour une conduite d'air tertiaire entre un refroidisseur
de scories et un four de calcination d'une ligne de four de scories ayant au moins
un dispositif de fermeture (80) qui peut être inséré dans la conduite d'air tertiaire
(10) pour la fermer et qui ne réduit pas davantage la section transversale de la conduite
d'air tertiaire (10),
caractérisée en ce que
l'unité coulissante (1) comprend de plus au moins un dispositif de commande (60) étant
configuré pour être inséré dans ladite conduite pour réduire la section transversale
d'une section de la conduite d'air tertiaire.
2. L'unité coulissante (1) de la revendication 1,
caractérisée en ce que
le dispositif de commande (60) est disposé sur le côté contre le vent du dispositif
de fermeture (80).
3. L'unité coulissante (1) de la revendication 2,
caractérisée en ce que
le dispositif de commande (60) est soutenu a son côté sous le vent par le dispositif
de fermeture (80).
4. L'unité coulissante (1) de l'une des revendications précédentes,
caractérisée en ce que
le dispositif de fermeture (80) possède au moins deux segments de fermeture (82, 83)
guidés en parallèle l'un par rapport à l'autre.
5. L'unité coulissante (1) de la revendication 4,
caractérisée en ce que
au moins un premier segment de fermeture (82) est amovible dans un guide d'au moins
un autre segment de fermeture (83).
6. L'unité coulissante (1) de la revendication 4 ou 5,
caractérisée en ce que
au moins l'un des segments de fermeture (82) possède au moins une prise (85) pour
au moins un autre segment de fermeture (83) du dispositif de fermeture (80).
7. L'unité coulissante (1) de l'une des revendications précédentes,
caractérisée en ce que
le dispositif de commande (60) possède au moins un transporteur (62) avec un revêtement
résistant à la chaleur.
8. L'unité coulissante (1) de l'une des revendications précédentes,
caractérisée en ce que
le dispositif de commande (60) possède une plaque autoportante du matériau résistant
à la chaleur.
9. L'unité coulissante (1) de l'une des revendications précédentes,
caractérisée en ce que
le dispositif de commande (60) et/ou le dispositif de fermeture (80) possède au moins
un canal pour un agent de refroidissement.
10. L'unité coulissante (1) de l'une des revendications précédentes,
caractérisée en ce que
la surface du côté du dispositif de commande faisant face au courant d'air tertiaire
est plus petite que la section transversale de la conduite d'air tertiaire.
11. Une installation pour produire des scories de ciment avec au moins
- un four
- un four de calcination,
- un refroidisseur de scories et
- une conduite d'air tertiaire pour transporter de l'air préchauffé dans le four de
calcination
caractérisée en ce que
l'installation possède au moins une unité coulissante (1) de l'une des revendications
précédentes.